1. Field of the Invention
This invention relates to a process for treating sulphur containing ores, and more particularly, is directed to a process for recovering copper, silver, zinc and lead from a partially roasted pyrite concentrate by chloride leaching.
2. Description of the Prior Art
In the past a variety of processes have been used for the extraction of metals and non-metals from sulphide ores. In many of these processes the sulphide ores have been subjected to concentration steps prior to recovery of specific metal values contained therein. Most of these processes suffer from the same disadvantage, in that they are incapable of recovering all the metal values in the ore using one economical process.
In addition many of the prior art processes have been limited to specific ores and concentrates which have a high concentration of the desired components to make the removal of those components economically feasible.
In a number of the above mentioned processes the sulphide ore concentrates are subjected to chloride leaching techniques to recover the metal values contained therein. Some of these processes include a thermal decomposition of the pyrite concentrate prior to the chloride leaching step. However, in many of these prior art processes the pyrite concentrate matrix is virtually unattacked by the initial heating of the pyrite and therefore a significant portion of the metal values occluded in the pyrite is lost, since they cannot be reached by the leach solution.
The process of the present invention provides for the opening of the pyrite matrix prior to the leaching stage thereby increasing solution penetration and resulting in higher percentages of metal extraction.